docs: def _get_stddevs(self, C, stddev_types, num_sites):
          """
          Return standard deviations as defined in tables below
          """
          assert all(stddev_type in self.DEFINED_FOR_STANDARD_DEVIATION_TYPES
              for stddev_type in stddev_types)
          stddevs = [np.zeros(num_sites) + C['SigmaTot'] for _ in stddev_types]
          return stddevs